A light-emitting diode (LED) chip including a semiconductor multi-layered film is used for a light source for a backlight of liquid crystal, an indicator such as a meter, a light source for a display, a light source for a read sensor, or the like. In particular, recently, owing to the increase in the optical output of an LED chip and the decrease in a wavelength of light taken out from the LED chip, it is considered to apply the LED chip as an illumination light source. For example, JP 2003-124528 A proposes a light-emitting module capable of realizing high optical output by mounting a number of LED chips on a card-shaped substrate at high density.
The LED chip generates a great amount of heat during use, so that some heat-dissipating means generally is used when applying the LED chip to a light-emitting module. For example, in the light-emitting module in the above-mentioned JP 2003-124528 A, an LED chip is mounted on a metal substrate via an electrical insulating layer made of an organic material, whereby the heat generated from the LED chip is dissipated from the metal substrate via the electrical insulating layer. However, according to this heat-dissipating means, the organic material constituting the electrical insulating layer is degraded due to the heat and light generated by the LED chip, with the result that cracks may be generated in the electrical insulating layer. In the case where cracks are generated in the electrical insulating layer, a leakage current is generated via the cracks when the LED chip is supplied with electricity. Therefore, it may become impossible to allow the LED chip to emit light.